The term packaging device is intended to refer to any packaging which allows the sale, the transport, the protection and the storage of the product which it contains.
The term application device is intended to refer to any device comprising means for applying and dispensing a composition, in particular a cosmetic composition, to keratinic materials, such as skin, or keratinic fibres (lashes, hair . . . ).
It is known, in particular from document FR 2 884 500, to provide a piston which slides in the tubular body of a receptacle which is intended to receive an applicator comprising an application element which is arranged at the end of a rod, so that, when the applicator is introduced, the tubular piston is moved along the body so as to compress the product stored in the receptacle. The product is thus confined to the bottom of the tubular body and is held in contact with the application element, whilst being separated from ambient air, which promotes the preservation thereof.
The use of such a piston is effective with regard to the removal of the product by the applicator and the preservation of the product. However, the travel of the rod of the applicator through the piston and movement of this piston generate excess pressure or reduced pressure within the receptacle, which lead to introduction or removal forces of the applicator relative to the receptacle which differ in accordance with the position of the applicator along the introduction or removal path thereof. This phenomenon which is referred to as “pulsing” is unpleasant for the user and can bring about irritating noises. Furthermore, the mechanical resistance counter to the movement of the applicator relative to the receptacle is perceived to be an irritation by the user.
The object of the invention is to provide a solution to this non-homogeneous nature of the retention forces applied to the applicator during the movement path thereof.